Can be used for items such as Linux/UNIX man pages.
Example:
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<refentry>
<refmeta>
<refentrytitle>ls</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refsynopsisdiv><title>Synopsis</title>
<synopsis>
ls (options)... (file)...
</synopsis>
</refsynopsisdiv>
<refsect1><title>Description</title>
<para>List information about the files...
</para>
<!--...-->
</refsect1>
<!--...-->
</refentry>